hi xaxoto, i have same problem a few days ago, but i use datagridview not listbox, i think it has same logic, see here : My link

here is the clue :

'declare a variable as string and asign it as empty string or ""
'create a loop for listbox1
'check if your variable that you declare before has the same value or not with your listbox1 items
'if not, set your variable value to listbox1 item that has a same value
'add your variable to listbox2
'end if